The present invention relates to an analog-display electronic watch and is concerned with the problem of assembling the components of the watch in the casing thereof, the components essentially comprising a motor, spindles for the hands, gears coupling the motor to the spindles, a cell for supplying power to the motor, and a printed circuit carrying circuits for controlling the motor, including a quartz crystal resonator. For simplicity the term "spindles" is used to embrace both arbors and pipes.
Conventional analog-display electronic watches have a movement which is housed in a casing provided with a glass. The support structure of the movement is formed by two plates and intermediate bridge members which are connected together by pillars. The gears, the hands spindles and the rotor of the motor are mounted rotatably in bearings which are fixed with respect to the different bridge members or plates. The printed circuit is also fixed on one of the plates, with a housing for the cell also being provided in the movement.
In order to reduce the overall thickness of the watch, it has already been proposed that the support structure of the movement can be omitted, and the movable components and the fixed components can be mounted directly on the bottom of the casing and possibly on the inside surface of the dial. In that case, there is no longer any movement, in the strict sense. This construction which is disclosed in French patent application No. 79 21 862 makes it possible very substantially to reduce the thickness of the watch, but producing such a watch is a delicate operation. Therefore, this construction cannot be applied to a watch of ordinary quality.
For the same purpose, it has also been proposed that the gears may be mounted in an overhung or cantilever position on a single plate. The motion members are mounted rotatably on ball-type micro-bearings which are themselves mounted on lug or stud portions forming an integral part of the plate. The wheels or pinions of the same gear are therefore necessarily disposed on the same side of the plate. A design of this kind is disclosed in Swiss Pat. No. 610178. This construction once again is fairly complex, both from the point of view of production and assembly of the watch. In addition, the Swill patent only concerns a mechanical watch, and therefore does not solve the problem of fitting the motor.
French Pat. No. 76 15 399 discloses a watch movement of conventional type, with two base plates, but in which the stator of the motor forms an intermediate bridge member in which one of the pivots of certain wheels is rotatably mounted, the other pivot being mounted in one of the base plates. This design therefore makes it possible to save the cost of an intermediate bridge member, but it does not substantially satisfy the overall structure of the watch and does not provide for any reduction in thickness.